package website.digitalocean.chapter15;

/**
 * 观察者接口
 *
 * @author: longhc@citycloud.com.cn
 * @since: 2023/2/15 14:47
 * @version: 1.0
 */
public interface Observer {
    /**
     * 监听者收到通知，并获取 message
     */
    void update();

    void setSubject(Subject subject);
}
